WavReader: Add a custom move constructor.

  - The compiler-provided default move constructor is buggy because the "moved-from" class has the file closed in the destructor.
  - Not used in codebase right now, but better to implement it properly or delete it.
  - Similar to `WavWriter`.

PiperOrigin-RevId: 641883579

iamf/cli/tests/wav_reader_test.cc

@@ -13,8 +13,10 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <cstring>
 #include <filesystem>
 #include <string>
+#include <utility>
 #include <vector>
 
 // Placeholder for get runfiles header.
@@ -168,5 +170,37 @@ TEST(WavReader, OneFrame32BitLittleEndian) {
   EXPECT_EQ(wav_reader.buffers_, expected_frame);
 }
 
+TEST(WavReader, IsSafeToCallReadFrameAfterMove) {
+  const size_t kNumSamplesPerFrame = 1;
+  auto wav_reader =
+      InitAndValidate("stereo_8_samples_48khz_s16le.wav", kNumSamplesPerFrame);
+  auto wav_reader_moved = std::move(wav_reader);
+
+  EXPECT_EQ(wav_reader_moved.ReadFrame(), 2);
+  const std::vector<std::vector<int32_t>> kExpectedFrame = {
+      {0x00010000, static_cast<int32_t>(0xffff0000)}};
+  EXPECT_EQ(wav_reader_moved.buffers_, kExpectedFrame);
+}
+
+template <typename T>
+std::vector<uint8_t> GetRawBytes(const T& object) {
+  std::vector<uint8_t> raw_object(sizeof(object));
+  std::memcpy(raw_object.data(), static_cast<const void*>(&object),
+              raw_object.size());
+  return raw_object;
+}
+
+TEST(WavReader, IsByteEquivalentAfterMoving) {
+  const size_t kNumSamplesPerFrame = 1;
+  auto wav_reader =
+      InitAndValidate("stereo_8_samples_48khz_s16le.wav", kNumSamplesPerFrame);
+  const auto raw_wav_reader_before_move = GetRawBytes(wav_reader);
+
+  const auto wav_reader_moved = std::move(wav_reader);
+  const auto raw_wav_reader_after_move = GetRawBytes(wav_reader_moved);
+
+  EXPECT_EQ(raw_wav_reader_before_move, raw_wav_reader_after_move);
+}
+
 }  // namespace
 }  // namespace iamf_tools

iamf/cli/wav_reader.cc

@@ -15,6 +15,7 @@
 #include <cstddef>
 #include <cstdio>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "absl/log/check.h"
@@ -54,6 +55,16 @@ WavReader::WavReader(const std::string& wav_filename,
   }
 }
 
+WavReader::WavReader(WavReader&& original)
+    : buffers_(std::move(original.buffers_)),
+      num_samples_per_frame_(original.num_samples_per_frame_),
+      file_(original.file_),
+      info_(original.info_) {
+  // Invalidate the file pointer on the original copy to prevent it from being
+  // closed on destruction.
+  original.file_ = nullptr;
+}
+
 WavReader::~WavReader() {
   if (file_ != nullptr) {
     std::fclose(file_);

iamf/cli/wav_reader.h

@@ -32,6 +32,9 @@ class WavReader {
    */
   WavReader(const std::string& wav_filename, size_t num_samples_per_frame);
 
+  /*!\brief Moves the `WavReader` without closing the underlying file.*/
+  WavReader(WavReader&& original);
+
   /*!\brief Destructor. */
   ~WavReader();